Blimey, I disagree with so much of what BusyLizzie61 said!
why pursue a job now.. when you've such a young child? Surely, that defeats the point of having had them?
Funny how no-one ever says that to fathers. I think the point of having DC is to enjoy a close relationship with your wonderful children, and also the satisfaction of helping them grow into amazing adults. She can do that quite happily with a full time job, as almost all fathers and many mothers already do.
will it be affordable to work paying for childcare for two
Even if childcare costs more than her take-home pay for a few years, the benefits to her career and financial independence are well worth it.
Why should your employer have to carry all that burden?
You're right. Her partner's employer should be taking half the burden.
So, really you may have to make a decision to stop working, reducing hours so have more flexibility or oh taking some dependency leave too.
Ermm... no. That would be a terrible idea, for all the reasons I gave in my previous post. The children's other parent needs to do his 50% share of the emergency time off. It's really hard to make someone step up if they don't want to, though. Sorry, OP - I have no ideas how. One thing I know for sure though is that OP reducing her hours certainly won't encourage him to step up.
neither of you is unreasonable
Yes, her partner is.
including him acting like a grown up and sorting his own laundry
Yes
when needed
No. Always. And all of his own other personal care. Plus at least 50% of the time, work and inconvenience of looking after a household and children. They both work full time. Why on earth should she be doing more than him on top of that?